In addition, chronic administration of the antidepressants enhances adult hippocampal neurogenesis in rodents1,48,49, The increased 5-HT neuron activity and reduced depression-like behaviors in Pten cKO mice resembles the effect of SSRI antidepressants, and we investigated the BDNF expression and neurogenesis in the hippocampus. The gene discussed is BDNF; the disease is major depressive disorder.